The invention relates to an internal combustion engine, particularly an Otto engine.
Exhaust recycling systems are provided in internal combustion engines, particularly in so-called Otto engines, for reducing emission of pollutants with the exhaust, particularly nitric oxide. Formation of nitric oxides is dependent on temperature and the oxygen content in the combustion chamber of combustion cylinders. By mixing the exhaust with a fuel-air mixture, both are reduced and the pollutant emission is decreased.
In a known exhaust recycliner system for an Otto engine with carburetor, a second metering member is designed as an annular throttle which connects an exhaust return line with an intake manifold downstream of the carburetor. The exhaust is fed under excess pressure to the gasoline-air mixture in the intake manifold via this annular throttle. The first metering member arranged upstream of change to the second metering member in the exhaust recycling flow, is constructed as a throttle valve which is coupled with the carburetor throttle valve by a rod linkage. At a low intake pipe pressure determined by the position of the carburetor throttle valve, the recycling portion of the exhaust fed to the intake manifold is determined by a position of the throttle valve in the exhaust return line. This throttle valve becomes inactive at a predetermined intake pipe pressure, and the exhaust recycling portion is exclusively determined by the annular throttle and decreases as the intake pipe pressure increasing. It is only permissible to recycle a relatively small amount of the exhaust with this exhaust recycling system is a drop in the output of the internal combustion engine is to be avoided.